Railway signaling



June 9,1931.

E. C. SASNETT RAILWAY SIGNALING 3 Shets-Sheet 1 Original Filed April 20, 1925 June 1931. E. c. SASNETT RAILWAY SIGNALING a Sh eets-Sheet 2 Original Filed April 20, 1925 gnoenl'o;

lllllll l l i li gu Jew- June 9, 1931. E. c. SASNETT RAILWAY SIGNALING Original Filed April 20, 1925 3 Sheets-Sheet 3 Patented June 9, 1931 UNITED STATES PATENT err-Ice EDWARD C. SASHETT, OE WASHINGTON,/DI8TBIGT OI OOLUICBIA, ASSIGIOB 1'0 m UNION SWITCH 6t. SIGNAL COMPANY, 01 SWIBBVALE, PENNSYLVANIA, A OOBPOBL- 1'10! OF PENNSYLVANIA RAILWAY SIGNALING application filed Apr-i120, 1925, Serial Io. 24,544. Renewed January 9,1981.

The present invention relates to railway signaling, and particularly to automatic train control systems of the continuous indication An object of the invention is to provide a continuous indication train control system which will respond only to the signaling energy used in the system. To this end the system of the present invention employs sig- 10 naling energy in the form of im ulses which are transmitted from the trac through a translating device on the vehicle and includes mechanism which is effective to hold the train control means at one indication only so lon as the signaling im ulses are being receive the said mechanism eing ineifective when influenced by signaling energy of any character unless that energy is transmitted throu h the translating device in the form of impu of the particular character used in the system.

In a preferred form of system embodying the invention the signaling energy is transmitted through the vehicle translating device in the form of impulses at regular fixed intervals apart and a timing deviceon the vehicleis so correlated with said impulses that indication means under the joint control of the translating device and the timing device will be held at one indication only so long as impulses separated by said fixed interval are being received. If impulses are received the interval between which exceeds or falls short of said fixed interval the indication means will move to its biased position, and this result will also follow it energy is received in the form of a continuous current or an alternating current. The system is thus immune to extraneous sources of current in so far as concerns the giving of a false clear indication. In systems heretofore proposed dependence is placed upon tuned circuits to render the train control immune to extraneous current. Tuned circuits do not afford that absolute assurance that the system will not give a false clear indication that the present system gives, as will be obvious to any electrical engineer. An additional advantage of the present system is that one character of current can be used to give any number of different indications on the vehicle, it only being neces- (in accordance with'the indication desired to be given and to provide devices on the vehicle responsive respectively to the different intervals separating said impulses. It is thus possible to give any desired number of indications on the vehicle with a single source of signaling current.

My invention provides a system of the above mentioned c aracter in which the track is divided into insulated blocks, each included in a closed track circuit having a source of energy normally connected to the rails so as to continuously energize the track relay, and'in which normally inactive motor devices are associated with each track relay and are rendered effective to interrupt the track current and cause current impulses to flow through the rails of a block when a vehicle enters that block and in combination with this track' system, a vehicle equipment having means to hold a signal and other train controlling mechanism at clear only while impulses are received from the track. A system of this character is very desirable for the reason that no false clear indication can be'caused therein by failure of the insulated joints separating the blocks; and for the reason that where the system is applied to any of the existing automatic block systems using wayside signals controlled by track circuits, no changes in the track relays, or in the intermediate signal controlling devices, are required; and for the reason that the code applying motor devices need be operated only when vehicles enter the respective blocks controlled by said devices; and for the reason that the'current impulses applied to the rails may be made relatively strong as compared with the normal track circuit current, since the impulses are of momentary duration and are applied to the rails of a block only during the time a vehicle is in that block,

The broad combination of trackway means to'supply interrupted or periodically varying current, together with cab equipment controlled by the influence of such current is not claimed herein, but this combination forms the subject matter of a copending up lication Serial No. 215,318, filed by Arba G.%Villiamson, on August 2."), 1927, for train control systems. i

Referring to the accompanying drawings,

which illustrate the invention in two very simple forms, all employing continuous current,

Fig. l is adiagrammatic view representing an embodiment of the invention;

Fig. 2 is a similar view showingmodilications; and

Fig. 3 illustrates a system similar to that shown by Fig. 2. but employing a plurality of codes of impulses.

Referring first to Figure 1, there is shown a track divided into block sections by insulated joints, only one complete section being shown. Connected across the rails at the entrance end of each block section is a track relay 10, 10' etc. and connected across the the rails at the exit end of each block is a source of current which, in the present instance, is a portion of a battery 11, 11' etc. a wire 12 permanently connecting an intermediate pole of said battery with one of the track rails, and a wire 13, a circuit controller l4 and a wire 15 connecting an opposite pole of said battery with the other track rail. Thus the track relays are normally energized by current flowing through the track rails from the battery 11 through the connections described. M

16 represents a timing device of any approved construction, one such device being located at each block junction. The timing device indicated on the drawings is a clockwork motor adapted to drive a wheel 17 at a predetermined constant speed. Where a mechanical motor is employed for this purpose there may be provided in connection with such motors automatic rewinding devices of known construction. Also driven by the clock-work is a toothed wheel 18 normally engaged by a pawl 19, whereby the clock-work motor is normally held inoperative. WVheel 17 is provided with a number of eqlyllii-angularly spaced projections, which w en the motor is operating are adapted to close and open a circuit controller 20 carried by the armature of a magnet 21, the projections of wheel 17 being effective to operate circuit controller 20 only when magnet 21 is energized and has thus raised the circuit controller into the path of said projections. Pawl 19 is operated by a magnet 22, so that when this magnet is energized the pawl will be withdrawn from engagement with wheel 18, releasing the clock-work which will then drive wheel 17 at a constant speed. Pawl 19 is provided with a projection engaging the center spring of circuit controller 14-, whereby when magnet 22 is energized the normal connection of battery 11, 11 etc. is interrupted and the battery is connected through conductor 23, circuit controller 20 and conductor 24. The magnets 21 and 22 are in a circuit from battery 11, a back contact of relay 10, line wire 25, a front contact of relay 10', conductor 26, magnets 21 and 22 and back tobattery 11 through common conductor 27. It will be clear, therefore, that when a train or vehicle, represented by the wheels and axle 28, enters the block shown it will deenergize relay 10 and close the circuit of magnets 21 and 22, if the block in advance, to which relay 10 is connected, is clear, thereby releasing the clockwork 16, raising the circuit controller 20 into the path of the projections on wheel 17 disconnecting the normal connection of battery 11' with the track rails and connectin the battery with said rails by way of the circuit controller 20, the net result being that the battery 11, or a portion thereof, will be intermittently connected across the track rails, the interval between successive connections of said battery to the track rails being substantially unvarying.

The present invention is not concerned with any particular means for transmitting the impulses through the translating device on the vehicle. The drawings show for this pur ose a pair of shoes sliding on the rails an connected to a magnet 29 by extremely low resistance conductors, but it is to be understood that this connection is merely illustrative and that any known means, conductive or inductive, and with or without amplifying means may be employed for rendering the translating device on the vehicle responsive to the current impulses flowing in the trackrails.

Magnet 29 controls the circuit or" a mag net 30 which operates a holding pawl 31 adapted to engage a toothed sector 82. Sector 32 is driven step-by-step in a clock-wise and carrying a, sector 41. A spiral spring 42 attached at its inner end to shaft 40 and at its outer end to some relatively stationary art of the apparatus urges the shaft with lts attached parts to the position shown in the drawings, a suitable stop 43 being provided. Sector 41 is provided with'a cam projection 14 which engages a contact spring 45 when sector 32has been driven through a predetermined number of steps from the initial position shown in the drawings and moves said spring into engagement with a companion spring 46 thus closing one gap in the circuit of a magnet 47. Magnet 17 has an armature 48 which engages a contact spring 49 when magnet 47 is energized and which remains in engagement with said spring for apredetermined interval subsequent to the deenergization ofn'iagnet 47. For accomplishing ,this result any suitable quick pick up and slow release for 1nag net47 may be provided. The means indicated on the drawings is a dash pot connected with the armature 48 allowing a quick pick up of the armature but retarding the opening movement thereof for a sufiicient time to maintain the spring 49 in engagement therewith during the interval between successive energizations of magnet 47, so that the circuit of the signal and train control mechanism, represented diagrammatically by a signal 50, is maintained closed so long as the interval between successive energizations of magnet 47 does not exceed a predetermined value.

The operation of the described devices is as follows: Normally the clock-work 16 on the track is held inoperative by pawl 19, but

' as before pointed out when a train enters a block, the block in advance of which is clear, the clock-work is released and operates to impress the voltage of battery 11', or any desired portion thereof, across the track rails thus transmitting electrical impulses through the vehicle relay 29 at regular intervals. It is to be understood that these impulses may be relatively strong since each impulse is of momentary duration and theimpulses are applied to the rails of a block only when that block is occupied by a vehicle. Thus it is possible to have on the vehicle a sensitive relay which will respond directly to the impulses with the consequent elimination of amplifying mechanism, altho it is to be understood that the invention is not limited to a relay thus directly actuated and indeed is not concerned with any particular relay or with any particular means for rendering the relay responsive to the current impulses flowing in the-track rails. Upon the reception of each impulse, relay 29 closes the circuit of magnet 30, which then withdraws the holding pawl 31 and driving pawl 33 from the teeth of sector 32, whereupon spring 42 returns the sector with its attached parts to the initial position shown, the stop 43 limiting the movement in this direction. Let it be assumed that impulses are transmitted through relay 29 at half second intervals and that magnet 34 is energized at intervals separated a tenth of a second, that is, that the release magnet 30 is energized twice every second and the driving magnet 34 is energized ten times every second. The cam 44 and contact spring 45 will then be positioned so that the cam will cause the springs 45 and 46 to engage when the sector 32 has been driven through an angle of five teeth. The position of the parts shown in the drawings is that assumed just after an impulse from the track has been received. From this position sector 32 will be driven through five steps by the intermittent energizationof magnet 34. At the fifth step,

with cam 44 engaging spring 45, an impulse from the track will be received causing magnet 29 to pick up its contacts. Contact 51, which closes an instant in advance of the closure of the contact coni rolling magnet 30, completes the circuit of magnet 47 which draws its armature to fully raised position. Following close on the energization of magnet 47, magnet 30 is energized withdrawing the holding and driving pawls from the teeth of sector 32, whereupon the parts return to initial position. Thus under clear conditions, the sector 32 and attached parts will operate through a phase of five steps from an initial position twice every second and at the completion of each phase of its operation will send an impulse through magnet 47 which willbe effective to restore the armature 48 to fully raised position. The retardation of armature 48 in its opening movement is so timed that so long as impulses are sent through magnet 47' at half second intervals apart, armature 48 will not break contact with spring 49, so that under these conditions the circuit of train control devices 50 will be maintained closed.

When a train enters a block with the block in advance occupied the circuits of magnets 21 and 22 will not be closed and hence the normal connection of the battery to the track rails will not be disturbed, a steady current will be transmitted through relay 29 which will maintain the magnet 30 energized and the pawls withdrawn from the teeth of sector 32, rendering the intermittent energizations of magnet'34 ineffective to step around this sector. Impulse's being no longer sent through magnet 47 the armature 48 will disengage contact 49 and the traincontrol mechanism will assume its biased position. 4

From the foregoing it will be clear that it is l a condition precedent to the es ablishment of a clear indication that impulses be transmii ted from the track through the translating device on' the vehicle continually and at a certain interval apart. Impulses separated by any other interval will be ineffective, as Well as continuous current or alternating current. It follows, therefore, that if the elements of the system be properly constructed, a false clear indica ion is extremely improbable.

The operating principle of the system illustrated by Figure 2 is exactly the same as that of the system described above, the only differences residing in the construction of individual elements. In the system of Figure 2, the timing device on the track is a constant speed motor. The drawings representa vehicle in the block shown in full with the block in advance clear. Under this condition a circuit is closed through a relay from battery 11, back contact of relay 10, line wire 25, front contact of relay 10, relay 60, conthe rails from the wayside batteries.

ductor 61 and back to battery through the common wire 27. The picking up of relay 60 opens a connection from a portion of battery 1-1 to the track rails at back contacts 62, 33 and connects battery 11 with motor 641- through front contacts 65, 66 and impresses the full voltage of the battery through the circuit controller 67. Motor 64 therefore is operating at constant speed and is causing the apening and closing of the connection of battery 11 with the track rails at regular fixed intervals.

.The vehicle equipment includes a relay 68 connected to a pair of shoes sliding on the track rails and, therefore, adapted to be energized by the impulses transmitted through Relay 68 when energized closes the circuit of a solenoid 69 at front contact 70, said circuit including a battery 71. The plunger of solenoid 69 is connected to an arm 72 pivoted at 73. Pivoted coaxially with arm 72 is a ratchet wheel 74, the teeth of which are adapted to be engaged by a pawl 7 5 carried by arm 72.

- Rigid with ratchet wheel 74 is a toothed wheel 7 6 meshing with a small pinion 77 on the shaft of which is a fan 78. Upon the reception of each impulse, therefore, arm 72 will be drawn to the limit of its upward move ment and upon cessation of each impulse said arm will be drawn down by a spring 79, its downward movement being retarded by the connection thereof with the ratchet 74, gearing 76, 77 and fan 78.

At a certain point in the downward movement of the arm 72 said arm will engage a leaf spring 80 which is normally in contact with an upper spring 81. The downward movement of spring 80 thus produced will first cause said spring to engage a lower spring 82 while still maintaining contact with upper spring 81 and will then cause spring SO-to disengage upper spring 81. During the instant while spring 80 engages both springs 81 and 82, if the relay 68 is energized, a circuit is completed through magnet 83 from.battery 71, front contact 84:, conductor 85, magnet 83, conductor 86, springs 82, 80 and 81 and conductors 87 and 88 back to battery.

The timing of the downward movement of the arm 72 is so correlated to the operation of circuit controller 67 that simultaneously with each closing of circuit controller 67 arm 72 is in the position where it causes the spring 80 to be in engagement with both springs 81 and 82. It will be observed that the circuit of magnet 83 is completed at the front contact 84 an instant in advance of the closing of the circuit through solenoid 69 at front contact 70, thus giving time for an impulse to be sent through the magnet 83 before solenoid 69 is energized to raise arm 72 and open the circuit of magnet 83 at the lower contact spring The armature magnet 83 is connected to a dash pot 89 so as to have a quick pick up and a slow release. If impulses are sent through the magnet 83 at predetermined inreception of each lmpulse an impulse from the vehicle carried battery will be "sent through the magnet 83, causing the latter to maintain the train control device 91 at a clear indication. It will also be understood that the vehicle carried mechanism will be ineffective to hold the train control device at clear indication upon the reception of continuous or alternating current or of current impulses unless the impulses are separated by the exact interval to which the mechanism is designed to respond.

As hereinbefore stated, one of the advantages of my system resides in the fact that any desired number of different indications can be produced in the vehicle through the use of only one character of current, since with one character of current any number of different codes can be transmitted and the vehicle can be equipped with indication devices respectively responsive to the different codes.

Thus, for example, in Fig. 3 I have shown diagrammatically a system employing two codes, each code consisting of regular impulses and the codes being differentiated by the interval between impulses. The track system illustrated in this View is the same as that shown by Fig. 2, except for the addition of a circuit controller 67 and a trafiic controlled switch 100 adapted to select the codes in accordance with the conditions of advance blocks.

From the description of Fig. 2, it will be understood that when a vehicle enters the block immediately in rear of the station illustrated in Fig. 3, the circuit of relay 60 will be closed through line wire 25, front contact of relay 10, the winding of relay 60, conductor 61 and common wire 27. Relay 60 when energized opens its back contacts 62 and 63 and thereby deenergizes the normal track circuit, which circuit includes a portion of battery 11', back contacts 62 and 63, and conductors 101 and 102. The picking up of relay 60 also closes front contacts and 66 and connects battery 11 to the terminals of motor 64 through the following circuit: fromthe upper pole of battery 11. conductors 103 and 104, front contact 66, conductors 105 and 106, motor 64, conductors 107 and 108, front contact 65 and conductor 109 to the lower pole of the battery. Motor 64: drives a worm 110 in mesh with a worm wheel 111 on a shaft 112 fixed to which are cam wheels 113 and 114 adapted respectively trollers 67 and 67 Gamwheel 113 is \provided with. two diametrically opposed projections, while cam wheel 114 is provided with four equi-spaced projections, so that switch 67' will be closed at twice the frequency of switch 67, that is, the impulses transmitted by switch 07' will be separated by one half the interval which separates the impulses transmitted by switch 67.

The circuit controllers 67 and 67 are adapted .to be selectively connected to the track rails in accordance with traflic conditions through any suitable means. Thus I have shown a switch 100 andhave indicated by dotted lines that it is operated by the dis tant signal 115. When the distant signal is at clear, indicating a clear condition for at least two blocks ahead of the signal, battery 11 will be connected'across the track-rails through circuit controller 67 by Way of the following connections: from the upper pole of battery 11, conductors 103 and 104, front contact 66 of relay 60, and conductors 105 and 102 to the lower rail; and from the lower pole of battery 11-, conductor 109, front contact 65, conductors 108, 115 and 116, circuit con-' troller 67, conductor 117, switch 100 and conductor 118 to the upper rail. On the other hand, when the distant signal is in a horizontal position, indicating that the second block in advance is occupied, the connections through controller 67 just described will be interrupted, and the lower pole of battery 11 will be connected to the upper rail through controller 67 by way of the following connections: conductor 109, front contact 65, conductors 108, 115 and 119, circuit controller67', conductor 120, switch 100 and conductor 118. Therefore when a vehicle enters a block and trafiic conditions are clear for at least two blocks in advance, it will receive impulses from the operation of controller ,67,'said impulses being separated by a predetermined time interval of any desired value; when only one block in advance is clear, it will receive impulses from the operation of switch 67 said impulses being separated by a time interval which is one half the interval between the impulses transmitted by switch 67; and when the train enters an occupied block, it will receive no impulses, since relay 10 being deenergized, relay 60 will not pick up.

The vehicle is equipped with decoding mechanism involving nothing more than a duplication of the mechanism shown in Fig. 2. The elements designated by the numerals 68to 89 are indentical with the correspondingly designated elements of Fig. 2 and therefore need not again be described. In Fig. 3 the circuit controlled by magnet 83, which is intermittently energized when the code transmitted by controller 67 is received,

to operate circuit conincludes. a magnet 90 which may control a signal or other train governing device. The circuit of this magnet is from the upper pole of battery 71, conductors 88 and 95, the dash pot controlled contacts of magnet 83, conductor 94, magnet 90, and conductors'93, 92 and 91 to the lower pole of the battery. Magnet 90 therefore will be energized so long as the code transmitted by controller 67 is being received.

' \Vhen the code transmitted by controller 67 is being received, magnet 83 will be intermittently energized, while magnet 83 will not be intermittently energized. This is true because the code transmitted by controller 67 f has twice the frequency of the code transmitted by controller 67, so that when the code transmitted by controller 67' is being received arm 7 2 will move spring 80 to cause electrical connection of springs 81, 82 at the end of each interval between impulses, but at the end of this interval arm 7 2 will not have moved far enough to actuate spring 80. 'The circuit of magnet is from the upper pole of battery 71, conductor 88, the dash-pot controlled contacts of magnet 83, conductor 96,

magnet '90, conductor 97, contacts 98 (which are closed only when magnet 90 is deenergized) and conductors 92 and 91 to the lower pole of the battery. This circuit of magnet 90 is led through the contacts 98 for the purpose of preventing a possible simultaneous.

energization of the two magnets 90 and 90.

It is a familiar practice in this'art to thus electrically interlocked two or more signals or other devices, and I do not claim as any part of my invention this particular arragement.

The specific device shown in Fig. 3 for selecting the codes in accordance with the position of a distant signal also forms no part of my invention, and'is illustrated merely to show one simple form of traffic controlled means for selecting the codes. of difi'erent codes may of course be employed,

' and the selection of the codes'in an automatic system will of course be automatic, that is through the operation of some sort of trafiic controlled means.

Although all embodiments of the invention as described employ direct current energy, it is quite obvious that alternating energy maybe substituted and that this alter nating energy may be transmitted to the vehicle carried translating device inductively and through an amplifier, in a manner well understood in this-art for a number of years prior to the filing of my application.

Having described my invention what I claim as new is:

1. A code continuous indication system for the automatic control of railway vehicles, comprising a stretch of track dividedinto insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of electrical energy connected Any number across the rails at the exit end of each block, traflic controlled means for disconnecting the source of energy from the exit end of a block when a vehicle enters therein and for intermittently connecting a source of hi her potential across the exit end of said lock to cause relatively strong current impulses separated b a fixed time interval to flow in the rails 0 said block, in combination with a vehicle travelling on the track, a relay on the vehicle responsive to said current impulses, a timin device on the vehicle controlled by the ve icle relay, and train governing means controlled by said timin device and adapted to be held at one indication only so long as impulses are received from the track.

2. A track circuit system comprising, in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of electrical energy connected across the rails at the exit end of each block, and normally inactive means controlled by the track relays operating under safe trafiic conditions for disconnecting the source of energy from the exit end of a block when a vehicle enters that block and for intermittently connecting a source of higher potential across the ralls at the exit end of said block to cause relatively strong current impulses separated by a predetermined time interval to flow through the two rails of said block in series.

3. In an automatic train control system operatedby continuous current, in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a battery connected across the rails at the-exit end of each block,and normally inactive means op-' erating to disconnect the battery from a block when a vehicle enters that block and to connect a battery of higher potential periodically to said block to cause periodic current impulses in the rails separated by a fixed time interval, said means being under the control of traific conditions in advance.

4. A code continuous indication system for the automatic control of railway vehicles comprising, in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of electrical energy connected across the rails at the exit end of each block, normally inactive means operating when a vehicle enters a block to disconnect the source of energy connected to that block and to connect a source of higher potential intermittently to said block to cause relatively strong current impulses to flow through the two rails of the block in series, a vehicle on the track having a relay responsive to the impulses, decoding mechanism controlled by said relay, and a signalgoverned by said decoding mechanism.

' 5. In an automatic train control system operated by continuous current, vin combination, a stretch of track, divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a battery connected across the rails at the exit end of each block, and normally inactive means operating to disconnect the battery from a block when a vehicle enters that block and to connect a battery of higher potential periodically to said block to cause periodic impulses in the rails, said means being under the control of traflic conditions in advance.

6. A train control system comprising, in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of electrical energy normally connected across the rails at the exit end of each block, a motor adjacent each block junction, a circuit controller operably connected to each motor, a line circuit for each block which controls the motor at the exit end of the block and which is in turn controlled by the track relay at the entrance end of the block, said line circuit also controlling the connection of the source of energyat the exit end of the block, a second source of energy associated with each circuit controller and adapted to be connected across the rails at the exit end of the block through its associated circuit controller and through contacts controlled by the track relay connected to the block next in advance, whereby when the track relay at the entrance end of a block is deenergized, the motor atthe exit end of the block will be set in operation, the source of electrical energy normally connected to the exit end of the block will be disconnected, and said second source of energy Will be intermittently connected across the rails inaccordance with traffic conditions.

7. In a code continuous indication system for the automatic control of railway vehicles, in combination, a stretch of track divided into insulated blocks, a track relay and a source of electrical energy connected across the rails at the entrance and exit ends, respectively, of each block, a motor adjacent the exit end of each block, a circuit controller operated by each motor, a local circuit for each motor, a line circuit for, each block including a relay whichcontrols the local circuit of the motor at the exit end of the block and which is in turn controlled by the track relay at the entrance end of the block, said relay also controlling the connection of the source of energy at the exit end of the block, and a source of energy associated with each circuit controller of higher potential than that of the first mentioned source and adapted to be connected across the track rails at the exit end of the block through the circuit controller and through contacts controlled by the track relay connected to the block next in advance, whereby when the track relay at the entrance end of a block'is deenergized, the motor at the exit end of the block will be set in operation, the source of electrical energy normally connected to the exit end of the block will be disconnected, and the source of higher potential will-be intermittently connected across the rails in accordance with traffic conditions to produce a code of relatively strong current impulses in the rails. v s

8. In a coded continuous train control sys- H tern, in combination, a stretch of track divided into insulated blocks, a normally energized track circuit for each block, means for selectively applying coded current to each block in accordance with traffic conditions ahead, trafiic controlled means for taking track circuit energy off of the rails and putting coded current on to'the rails, car-carried means including a relay which is re-.

sponsive to the coded current, decoding mechanism controlled by said relay, and secondary circuitsselectively controlled by said decoding means. v

9. A code continuous indication system for the automatic control of railway vehicles comprising, in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of elect-ri- -cal energy connected across the rails at the exit end of each block, normally inactive means operatlng when a vehlcle enters a block to interrupt the connection of the source of energy to that block and cause discrete current impulses separated by a fixed time interval toflow from said source of energy through the two rails of the block in series, said means being under the control of the track relay connected to the block next in advance and being efiect-ive to cause current impulses separated'by said'time interval to flow in the rails of the rear bloc-k only when said track relay is continuously energized, a vehicle on the track having a relay responsive to the current impulses, and train governing mechanism controlled by said relay and adapted to be held at safe indication onlyrso long as impulses separated by said time interval are received from the track.

10. A railway traflic controlling system, comprising in combination, a stretch of track including an insulated block, means at the exit end of the block providing two paths through which sources of electrical energy may be connected across the track rails, one of said paths being normally closed to effect an uninterrupted flow of current through the rails, and means actuated when a vehicle entersthe block for opening said normally closed path and for periodically opening'and closing the other path to cause track including an insulated block, means at the exit end of the block providing two paths through which a source of electrical energy may be connected across the track rails, one ofsaid paths being normally closed to efiect an uninterrupted flow of current through the rails and the other path being normally open, and means actuated when a vehicle enters the block for opening said normally closed path and for periodically closing the other path to cause current impulses to flow through the two rails of the block in series 12. A railway traflic controlling system comprising in combination with a stretch of track including an insulated block, a track relay and a source of electrical energy connected across the rails respectively at the entrance and exit ends of the block, switch mechanism at the exit end of the block pro viding two paths in parallel through which current may flow from said source of energy to the track rails and through the two rails in series, and means actuated only when the track relay is deenergized to interrupt the flow of current through one of said paths and to cause an interrupted current to flow through the other path.

13. A railway trafiic controlling system comprising, in combination with a stretch of track including an insulated block, a track relay and a source of energy connected across the rails respectively at the entrance and exit ends of the block, a motor at the exit end-of the block normally inactive, a circuit controller periodically operated by the motor, and means actuated when a vehicle enters the block for interrupting the normal connections of the source to the track and inserting said circuit controller in the track circuit connections to cause separated current impulses to flow through the two rails of the block in series.

14. A railway traflic controlling system comprising, in combination with a stretch of track including an insulated block, a track relay and a source of energy connected across the rails respectively at the entrance and exit ends of the block, a motor at the exit end of the block, a circuit controller periodically operated by said motor, and means actuated when a vehicle enters the block for interrupting the normal connections of said source to the track and inserting said circuit controller in the track circuit connections to cause separated current impulses to flow through the two rails of the block in series.

15. A railway trafiic controlling system comprising, in combination with a stretch of I a vehicle enters the block for interrupting the normal connections of said source to the track and inserting said circuit controller in the track circuit connections to cause separated impulses to flow through the two rails of the block in series.

16. In an automatic train control system,

in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of energy normally connected across the rails at the exit end of each block, and normally inactive means operating when a vehicle enters a block to interrupt the connection of the source with that block and cause periodic current impulses to flow in the rails, said means being under the control of traffic conditions in ad- Vance.

17. In an automatic train control system, in combination, a stretch of track divided into insulated blocks, a track relay connected across the rails at the entrance end of each block, a source of energy normally connected.

I vance' and being rendered efiectivewhen the rear track relay is deenergized and the other track relay is energized.

18. In a coded continuous train control sys-' tern, in combination, trackway means includ- -ing normally energized track circuits, means for applying coded direct current to the track rails in accordance with trafiic conditions ahead, and trafiic controlled means for deenergizing said track circuits during appli cation of cod-ed direct current to such track rails, car carried receiving and decoding means continuously responsive to the presence of coded current and a secondary circuit controlled by said receiving and decoding means.

19. In a code continuous indication system, in combination, trackway means including normally energized track circuits, means for applying coded current to the track rails in accordance with traffic conditions ahead, and trafiic controlled means for deenergizing said track circuits during application of coded current to such track rails, car carried receivconditions in advance of said section, and

means for closing said first circuit when a train enters said section.

= 21. In combination, a section of railway track, a normally open circuit including an electromagnetic device, a second circuit controlled by said device and by trafiic conditions in advance of such section for supplying train governing current to the rails of the section periodically interrupted in accordance with one code or another, and means for closing said first circuit when a train enters said section.

22. In combination, a section of railway track, a normally open circuit including an electromagnetic device, two contacts operated by said device in accordance with two codes, a source of current, a second circuit for supplying current from said source to the rails of said section through one of said contacts or the other depending upon traflicconditions in advance of said section, and means for closing said normally open circuit when a train enters said section.

23. In a coded continuous train control system, in combination, trackway means including normally energized track circuits, means for applying coded direct current to the track rails in accordance with traffic conditions ahead, and trafiic controlled means for deenergizing said track circuits during application of coded direct current to such track rails, car carried receiving and decoding means continuously responsive to the presence of coded current, and secondary circuits selectively controlled by said receiving and decoding means.

24. In a coded continuous train control system in combination, a stretch of track divided into insulated blocks, a normally energized track circuit for each block, means for selectively applying coded direct current to each block in accordance with traflic conditions ,ahead, traflic controlled means for taking track circuit energy off of the rails and putting codeddirect current on to the rails, car carried receiving and decoding means continuously responsive to the presence of coded current, and secondary circuits selectively controlled by said receiving and decoded means.

25. In a coded continuous train control system, in combination, trackway means including normally energized track circuits,

means for applying coded current track rails in accordance with trafiic conditions ahead, and trafiic controlled means for deenergizing said track circuits during application of coded current to such track rails, car carried receiving and decoding means continuously responsive to the presence of coded current, and secondary circuits selectively controlled by said receiving and decoding means.

26. In a coded continuous train control system, in combination, a stretch of track divided into insulated blocks, a normally energized track circuit for each block, means for selectively applying coded current to each block in accordance with trailic conditions ahead, traflic controlled means for taking track circuit energy off of the rails and putting coded current on to the rails, car carried receiving and decoding means continuously responsive to the presence of coded current, and secondary circuits selectively controlled by said receiving and decoding means.

27. In a coded continuous train control system, in combination, a stretch of track divided into insulated blocks, a normally energized track circuit for each block, means for each block responsive to traflic conditions in advance for at times supplying the rails of the block with periodically interrupted train governing current, means for deenergizing the track circuit of each block when train governing current is being supplied to such block, and car carried governing mechanism including decoding means responding uniquely to said train governing current.

28. In a coded continuous train control system, in combination, a stretch of t'rack divided into insulated blocks, a normally energized track circuit for each block, code supplying mechanism controlled by each track circuit for at times supplying the rails of the block next in rear with periodically interrupted train governing current, means for deenergizing the track circuit of each block when train governing current is being supplied to such block, and car carried govthe code of such train governing current.

signature.

erning mechanism including decoding means responding uniquely to said train governing current.

29. In a coded continuous t'rain control system, in combination, a stretch of track divided into insulated blocks, a normally energized track circuit for each block, code supplying mechanism for each block for supplying the rails of the block with train governing current periodically varied in accordance with different codes depending upon trafic conditions ahead, means for deenergizing the track circuit of each block when train governing current is being supplied to such block, and car carried governing mechanism EDWARD G. SASNETT.

to the selectively and continuously responsive to 

